Trematodon ambiguus (Hedw.) Hornsch., Flora 2: 88. 1819. Dicranum ambiguum Hedw., Sp. Musc. Frond. 150. 1801. Syntypes. Sweden, Austria.

 Plants scattered, yellowish green, terricolous; stems 3–10 mm long. Leaves evenly spaced, flexuous-spreading when wet, 2–3 mm long, oblong and clasping at base; apex abruptly contracted to a long awn; margins erect, entire; costa percurrent, smooth, ventral surface abruptly expanding at base of awn and filling the upper leaf; upper cells quadrate to shortly rectangular, thick-walled, basal cells narrowly long-rectangular to rhomboidal, whitish yellow, thin-walls. Autoicous. Setae 7–16 mm long, yellow; capsules inclined, yellow or red, urns ellipsoidal, 1.0–2.0 mm long, neck 1.2–1.5 mm long, as long as or a little shorter than the urn; annuli deciduous, revoluble; opercula rostrate, 1.0 mm long; stomata phaneropore; peristome teeth red, lanceolate, vertically striate. Calyptrae yellow, 1.5 mm long. Spores papillose.